Honestly that sounds horrible. In most of the civilized modern world that problem is solved tho and people pick up after their dogs
Having said that, I've observed four cases where dog poop is more likely left behind.
1. Small dogs - owners of small dogs seem far more likely to leave dog poop behind. Perhaps because they think the poop is itself small?
2. Older owners (often owners of small dogs, but not always) - seem to care less.
3. Off leash dogs in parks - will often poop at the far edges of parks while their owners chat. Edges of parks and near bushes are minefields.
4. Rainy days - people just want to get home, clean off their dog and be done. So they seem more likely leave poop behind.
problem is that it requires municipalities and counties to take ownership and they don't give a shit and thus we get the shit we deserve
Pet owners should know to bring bags with them, as they are taking the pet out for it to shit somewhere other than their yard.
It's 100% an asshole pet owner problem. Owning a pet that is shitting somewhere other than your own yard means bringing bags on walks and being prepared to hold that shit filled bag in your hand for the rest of the walk until you can throw it away at home.
It can be partially mitigated by having trashcans and poop bag dispensers, but I've stepped in dog shit next to a poop bag dispenser. Because having trashcans and bags be available doesn't change asshole pet owner habits.